Telephone system



c. KEDDY TELEPHONE SYSTEM Filed Jan. 5, 1922 Patented Z d,

UETEQ stares l at.

TELEPHUHE ni zilici-iticn filed Jianiiar 1322.

it may conccmt:

known that l. CLIFFORD L. l it' the tiling of Great Brita u vnn. in the count of iiilassachiisetts, have in phone Systems, of which the tollowinga SPGCliICZlUOIL My invention relates to telephiinie sys enis and it has for its object to improve the construction and mode 01 operation of the same.

Telenhone s stenis have heretofore been so constriicted that when the central ooerator called a subscriber it was impossible,

cept when the subscriber answered the call of the central station, for the central operator to know whether or not the subscriber was absent from his station.

When the central operator plugs in to call a siihscribei: the supervisory lamp of the called subscriber at the central station is brightly lighted, and ii the subscriber at the station being called answers the central operators bell signal and removes his receiver from the hook, the

upervisory lamp of the called subscriber at the central station is diinincd. thus signals hscriber has responded to the bell lUS diiiin'iinn' of the calling lanip at t tral station is occasioned by the ren'mval 1 called ie central operator that men from its book of the receiver at the calleo subscribefis station and said laiiip at the central station remains diinnied so long as the called subscriber maintains his receiver oil" the book.

When the called subscriber replaces his receiver upon the hook this siipervisorv lainp at central station is re- HtOltCl to its bi- 'htl lighted condition, thus part of the central operators time in a fruitless etliort to secure a response from the called stat-ion but also subjecting persons the ed the use of a line to the exclusion of icrs tor an objectionally long period of 1c. without rcsul or profit to the telesei-iai 527,266.

""cinit v ot the called station to the ii "'aiic. of the continuously ringing bell Also, under such circuni ing subscriber has monopostation. call COlTlPZlDyi lily invention aims to this UlJjGCllOlllblG feature of teleie bell circuit as describeth automatically operated or protoe central station which intornis operator that the subscriber is Utiier Aeatures of my invention are hereinno system constructed in accordance with l in ure v: of one of the subscribers stations. in liigiire l ot the ointed out.

he accompanying drawings: ureis a diagrammatic View of a teleon. and con'iprising two substations and central station.

9 is an enlarged diagrammatic drawings, A and B are entral FT ibers station (see Fig. 2), connected with one end of J1 P 1 11' A 1 oi the .iiiiiiaiv or tne induction coil 1. the o'her end of said winding connected by a wire a with a stacontact co-operating with the 1e hoot: H is connected by a wirebinding p1, t of the transn'iittcr c other binding post has connected the o4; vine wire a. One end of the secondary or induction 0011 l is connected by wire (-4 and the wire a with the Com tact a while the other end of said winding is connected by a wire al with one of the binding posts of receiver R. The other binding post of receiver it n is connected by wire (1- with one side of the condenser C,

the other side ot said condenser being connected, by a ,wire c with the line wire a. The usual bell magnet a has one end of its windingconnected with wire a by a wire while the other end of its winding is connected by a wire a, with a stationary contact a. This stationary contact is co operatively disposed with relation to a movable contact a connected by a wire 64 with line wire (1.. Thus, so far as described, the construction at each subscribers station is,

with the exception of the switch a, (L18, in

all respects the same as heretofore.

At the central station one of the multiple jacks connected to [Us line is shown at'a, and the answering jack and line lamp at a and a respectively. One of the multiple jacks of Fe line is shown at b and the answering jack and line lamp at b and 6 respectively. In the event that the subscriber, .1 1, for example, desires to call, he removes his receiver B from its hook H, thereby lighting the line lamp of, and the central operator sitting before the answering jack, plugs into the answering jack with the result that current is sent through the shank wire of the plug to the ring 0 of the jack and thence through the cut-off relay 0 to ground, thereby cutting off direct battery from the line at 0" and putting out the line lamp a. The circuit closed by the removal of the receiver B- from its hook H at station A is traced as follows: from ground at G, through wire 0*, line battery X, wire 0 relay 0, wire 0 (relay 0 being normally .le-energized), wires 0 and 0 to line wire (.6 of station A, primary 7), wire of, contact a hook H, wire 0., transmitter T, line wire a of station A, wires 0 and 0, switch 0 and wires 0 and 0 to ground. The closing of this circuit through relay 0 results in the closing of switch 0 which is in the circuit of line lamp a This circuit of line lam a is traced as follows: from ground through wire 0 battery 0, wire 0, lamp (4, wires 0 and 0 switch 0 and wires 0 and 0 to ground again. The receiver B being off the hook H at A when the central operator plugs into jack (4 current 'tiows out on the line through the windings l and 2 of the repeating coil, and thus the supervisory relay 0 is energized and the shunt circuit thereof being closed the supervisory lamp 19 does not glow. The circuit of supervisory relay 0 which is thus completed at jack (6 is traced as follows: from one side of battery X through wire 0, coil 1, the winding of relay 0, wire 0, key K, wire 0 wire 0 wire 0, line wire a of station A, primary p, wire a contact a hook H, wire a, transmitter T, line wire a of stat-ion A, wires 0 and 0 cord wire 0", switch K, wire 0, coil 2, and thence through wire 0 to the opposite side of battery X. At this stage the calling subscribers tra sm tter is fed. by current sent out through the repeating coil, direct battery is cut off the line, the circuit of line lamp a is open and the supervisory lamp 0 shunted out.

hen the operator at central inserts the calling plug into the jack 6 of the called subscriber, B, for example, the cut-off relay 0 is energized and direct battery cut oil the line at switch 0 thereof. The receiver at B being on the hook, the line is open both at the hook and at the condenser, so that no current-flows through the supervisory relay 0, and therefore the shunt around the lamp [2 is open and the lamp illuminated when the central operator first plugs into jack 6", said circuit being indicated by the arrows in Figure 1. Directly B removes the receiver from the hook to answer, the line is closed through the primary coil, hook and transmitter, and current flows from the battery X through the windings 8 and 4 of the repeating coil to the called tele hone at B, and the relay 0' is energized, wit 1 the result that the shunt around lamp 3? is closed and p is dimmed, and this is the state of things during conversation. The circuit closed through relay 0 through the removal of the receiver from the hook at the called station, and which results in the dimming of the supervisory lamp p when the called subscriber responds to the operation of his bell signal, ist traced as follows: from one side of battery X, through wire 0, coil 3, wire 0, the winding of relay 0, wire 0 key K, cord wire 0 wire 0 line wire a of station B, primary 7) at B, wire a at B, contact a at B, hook H at B, wire a at B, transmitter T, and thence through line wire a of station B, wire 0, cord wire 0, switch K, wire 0, coil 4i, and wire 0 back to the opposite side of battery X. This circuit through relay 0, however, is only completed in the event that the called subscriber removes his receiver from its hook, and heretofore the only sig nal transmitted to the central operator through this circuit has been the dimming of the supervisory-lamp p to inform the central operator that the. calledsubscriber has responded to her signal by removing the receiver from the hook. It is to be observed and remembered that the circuit through the relay 0 or 0 is broken at the switch K each time the central operator moves said switch from its normal position to ring the bell at the called subscribers station. It is also to be noted that the supervisory lamp p or p of the called subscriber has heretofore remained continuously brightly lighted until the called subscriber removed his receiver from the hook, the dimming of said supervisory lamp occasioned by the removal of the receiver from the hook being the signal to the central operator that the called subscriber has responded, and, as pointed out, this dimming of the supervisory lamp has heretofore been the only signal returned from the called station in response to the operation of the bell at that station.

In carrying out my invention 1 provide at each subscribers station a movable switch member (4 (referred to above), connected by a wire 11 with one of the line wires of that station and two stationary contacts a, (referred to above), and (0 It will be clear that when the movable contact a is in 'engagen'ient with the stationary contact a the operation of the apparatus at the subscribers station is substantially the same a heretofore, the signal bell a and condenser C being disposed in a shunt connecting the two wires as usual, so that when the central operator de resses key K a-fter plugging into the ca ling jack 1), the usual bell a will be sounded so long as contacts a and a are in engagement. The contact (0 is accessible *to the subscriber and is adapted to be manually adjusted by him so as to be engaged either with the contact a" or with the contact (0 The contact a is connected by a wire a with one end of the winding of a magnet a, the opposite end of said Winding being connected by a wire a with that portion of the bell shunt that is between the hell a and condenser C. The armature a of magnet (e carries a striker a cooperating with two bells 0, A spring a connected with an arm 04 projecting from armature a holds said arm against a stop c? wit-h armature 0/ at the limit of its movement away from the magnet. Resting upon arm (1 is a rod a freely movable vertically within a stationary guide (1, and at its upper end said rod carries a piston a loosely mounted within a stationarily supported cylinder 0, normally closed at its upper end by a valve a. This valve is hinged at a to the cylinder and near its middle is formed with a small vent hole a.

The rod (4 has fixed to it a laterally extending contact arm a co-operating with, but normally occupying a position below, and out of engagement with, a stationary contact 0 connected by a wire a? with one line wire a. As herein shown this wire a is joined to the wire (4 so that contact a is connected with line a through the primary g) of induction coil 1. The metal guide (4 is connected by a wire a with hook H, and through wire a and transmitter T with line a.

It will be understood that the outer pair of contacts of each key K and K is connected, as usual, by wires, not shown, with a generator. Also, that when the central operator depresses either key K or K the pair of middle movable contacts is shifted from the inner pair of contacts to the outer pair of contacts, thereby throwing the generator current onto theline to-ring the bell a at the subscribers station. \Vhe-n switch a is on contacts and the generator current is thus thrown onto the line the usual signal bell a is sounded, and this will be the condition of'things while the subscriber is present at his station. When, however, the subscriber is about to leave his station and desires to have the central operator informed of the fact that he is absent should he be called during hisabsence, then the subscriber shifts the switch member (0 over onto cont-act c and leaves it there until his return. Should a call be made for his station during his absence, the bell ringing generator current passes from line a through wire 56 switch member (618; contact a wire a; bell magnet (r wires (4 and a condenser C and wire a to the other line wire a. This causes magnet (L22 to attract its armature whose arm shoves the rod (4 upward carrying contact a against contact c5 and whose striker a sounds the lowermost bell a. This engagement of contacts a and a closes the shunt ca -a around bell magnet e for the generator current, thus cutting out the bell magnet o whose armature is restored to its normal position by spring a, thus causing the striker to sound upper bell a Rod 66 contact a and piston 66 then fall by gravity to their normal positions again, but slowly owing to the restricted air inlet a. The engagen'ient of contacts a and (n has the same effect upon the supervisory relay 0 or 0 as is produced when the receiver R is removed from the hook. That is, assuming that station A is being called by central, the depression of key K brings contacts a and (1 into engagement so that when key K is restored to normal position, relay 0 is energized and closes the shunt 0 0 and 0 at central, thereby dimming supervisory lamp 7). In other words, the supervisory lamp 79 shows bright when central plugs into As calling jack 6 but ismomentarily dimmed each time key K is restored after ringing As bell, and this informs the central operator that the subscriber at A is absent. As pointed out above. the circuit of relay 0 is opened at key K each time the operator depresses said key, so that while said circuit is thus open lamp 7) glows brightly, but each time key K is restored the circuit through relay 0 is closed at the key well as at a and a and lamp p shows dim and remains so until contact a moves down out of engagement with contact a. Thusduring ringing operations made to call the absent subscriber, the lamp p alternately shows bright and dim, whereas under normal conditions, (that is, with contact a" on contact a") the lamp 3) remains continuously bright during ringing operations During the upward movement of rod 0:

under the influence 01. the armature arm (0 the .piston a moves treely and unretardedly within the cylinder (W, the valve (6 being free to open outwardly. At the conclusion of the upward movement oit' piston 0, however, the valve (/9 closes, so that the descent of rod 0/ and parts carried thereby, including the contact arm a, is checked or retarded, so that said parts move clownwardly under the influence of gravity slowly, owing to the restricted vent port a. This insures the lamp p being maintained dim for an appreciable period of time after key K has been restored to its normal position.

It is intended that the subscriber upon returning to his station shall shift the con tact 0, back onto the contact a, but should he forget or neglect to do this, the sounding of the bells (4 upon the occasion of the first call after his return will remind him to do It will be clear to those skilled in this art that the only change necessary to be made in the system as heretofore constructed is the provision of the switch a -a in the conductor 0 the joining of conductor (0 with conductor (Z15 and the provision of a small number of additional parts at the subscribers station including magnet 0. and parts that are associated therewith, and that these parts may be made up or constructed as an attachment, including the switch a a that is comparatively inexpensive and easily applied to the subscribers instrument.

What I claim is:

1. A telephone system having in combination a plurality of stations; signal instruments at said stations; signal circuits connecting said stations; means through which a person at one station operates the signal circuit of the other station to call the latter, and means under the control of the person at the called station adapted to be manually adjusted so as to automatically produce a visual absent signal atthe calling station when the signal circuit of said called station is operated.

2. A telephone system. having in combination a plurality of stations; signal instruments at said stations; signal circuits connecting said stations; means through which a person at one station operates the signal circuit of the other station to call the latter, and means under the control of the person at the called station adapted to be manually adjusted so as to automatically operate the signal circuit of the calling station to proon. station operates the signal circuit o't'the other station to call the latter, and means under the control oi the person at the called station adapted to be manually ZKljUSQQCl so as to automatically operate the signal 011'- cuit ot the calling station to produce a visual absent signal at said calling station when the signal circuit of said called station is operated.

4. In a telephone system the combination with the two line wires at a subscribers station, of a normally closed main shunt circuit connected with said line wires; a bell in said main shunt circuit; a condenser in said main shunt circuit; a second shunt circuit around said bell having one end thereof connected with said main shunt circuit between said bell and said condenser; a relay in said second shunt; a normally open switch operated by said relay; a third shunt connected at its ends with said line wires and in which said normally open switch is arranged; and shunt controlling means adapted to be adjusted by the operator at the subscribers station to either open said main bell shunt circuit and close said second shunt circuit, or to open said second shunt circuit and close said main bell shunt circuit.

5. In a telephone system the combination with a plurality of subscribers stations each equipped with telephone apparatus including a transmitter, receiver, hook and bell; a central station equipped with central station apparatus including jacks, plugs, ringing keys, supervisory relays; supervisory-lamps and circuits for said instrumentalies, and line wires. connecting the subscribers stations with the central station, of means at each subscribers station that is normally inoperative but adapted to be set or adjusted by the subscriber so as to be operated by the ringing current to automatically control the supervisory lamp of that station at the central station to produce a visual signal indicating to the central station operator that the subscriber is absent from his station.

In testimony whereof I have atliXed my signature.

CLIFFORD L. KEDDY.

0. A telephone system having in com- I 

